Kad udjem podesevanja, i izaberem Chat, izbaci mi Registration failed..
I meni je istu poruku izbacivao kada kliknem na Chat Settings, a kako bi to u nasim novinama rekli, jedna stvar je resila problem
In the play store I installed Carrier Services (from Google) and Google Messages.
Open Google Messages, set it as default messaging app.
Went to settings > Chat Features to enable the new RCS chat. You will get a pop-up asking you to to enable RCS (you will have to give them your number, but its google, they already have it)
You may have to wait a bit for it to verify.
Once verified you jump back over into Samsung Messages, set it as the
default messaging app (should prompt you),
then go to settings > chat settings. It should let you in right away, then you can either keep the RCS chat on or turn it off.
You can now uninstall both Carrier services and Google Messaging.